To enable virtualization on a machine with a Z77X-UDH3 motherboard run the BIOS by hitting Del while booting the computer.
Once inside click on the BIOS Features tab and look for the Intel Virtualization Technology entry. If it's set on Disabled, set it on Enabled. Afterwards save the changes made to your settings and quit the BIOS using the last tab from the main tab-line.
In some cases when you try to get a virtual machine running with Virtualbox or similar virtualization software you will get an error stating that 'VT-X is not available'. This relates to BIOS settings which, depending on your processor, determine whether your computer is able to virtualize stuff. These settings are not set automatically however, so it's worth a look into your BIOS whether you can actually change the setting and if your processor allows it.
The keyword to look for in the settings is 'Virtualization', it's probably placed in some advanced tab if there are some of those in your BIOS.
To see how it's done with a Z77X-UDH3 motherboard by Gigabyte see this post: Gigabyte Z77X-UDH3
VirtualBox machines usually have two bars in their window to make working with them easier.
These however are a great disturbance if you want to take screenshots of your machines - even if you select to leave the window border, the menu bars will still be on them.
To remove the bars, it only needs a simple terminal command. Open one and enter following (make sure that no virtual machines are running):
/usr/bin/VBoxManage setextradata global GUI/Customizations noMenuBar,noStatusBar
Next time you start a VirtualBox vm, there won't be any menu bars. To restore them again, enter following into a terminal:
/usr/bin/VBoxManage setextradata global GUI/Customizations MenuBar,StatusBar
To uninstall VirtualBox Guest Additions on Ubuntu and similar operating systems, mount the virtual disk again that you used to install them - to do that, click on the Devices menu on the virtual machines top menu bar and select Install Guest Additions. If you get a pop-up about auto-start procedures just cancel it.
Now that the virtual disk is mounted, open a terminal and look for the contents of the disk in the /media folder.
In my case, the disk is named VBOXADDITIONS_4.1.10_76795. This name may vary depending on the version of VirtualBox you have installed. Now uninstall the guest additions (don't forget to adjust the path):
sudo sh /media/VBOXADDITIONS_4.1.10_76795/VBoxLinuxAdditions.run uninstall
You can uninstall the guest additions just like any other program on a Windows machine: Click on Uninstall a program in the Control Panel and search for the version you installed. Select it and click on the Uninstall button above the program list.
VirtualBox offers a feature that let's you treat windows opened in the running guest system almost as is they were native to the host system - you can drag them around on the host system, copy and paste texts between the system and only see the host's desktop while doing so:
(Windows 8 Release Preview guest system on a Linux Mint 12 host system in Seamless mode)
The requirement for Seamless mode to run is that the VirtualBox Guest Additions are installed. You can quite easily install them by clicking on the Devices menu on the the guest system's window menu and selecting Install Guest Additions... - follow the installer afterwards and reboot the guest system when you are told to. After the reboot you can enter Seamless mode by selecting the guest system's window and pressing right Ctrl + L.
Virtualbox, as most other virtualisation technologies, provides a service to establish shared folders between the host system and the virtualbox guest OS. For that, you need to install the Virtualbox guest additions. To do so on virtual desktops, just open the Devices menu and select Install guest additions....
Mount the CD and proceed like you are told to install the guest additions (steps differ in Windows and Linux). Before you can mount a shared folder you first need to create and/or assign one. Open the settings of the Virtualbox you are running and select the last menu item from the left pane, Shared Folders. Click the icon with the plus symbol on the right to assign a shared folder and give it a name, I'll use the name blabla for future reference. After assigning a shared folder you can mount them on your virtual machine.
On a Windows machine, open a cmd terminal and enter following (replace my folder name with yours):
net use x: \\vboxsrv\blabla
The folder will then be accesible from the Computer directory.
In Linux, open a terminal and enter following:
sudo mount -t vboxsf blabla /mnt
You can replace /mnt with any mount directory you like, of course.
The shared folder is now set up. You can push files there from the host or the guest system and access them from the other, which makes connecting both much easier than setting up an FTP or SSH connection.
If you try to install a Windows 7 system in a Virtualbox you will notice that there is no 3D support there - no feature of Aero works and the Desktop is shown in the Aero fallback mode without transparency.
But if you have the latest version of Virtualbox installed there is something you can do about that - experimental 3D support is now available with the help of a guest addition. To install it, open your virtual Windows 7 box and select Device > Install Guest Additions... to start:
Wait a second for the next window to pop up and click Run VBoxWindowsAdditions.exe:
Follow the setup until you can choose what additions to install. Select Direct 3D support (experimental). As it says, it is experimental so you shouldn't use it on production systems - make sure to have backups made of everything important:
When the warning appears, don't click on Yes blindly - that will make you cancel the installation. Read instead and click on No:
Follow the last steps of the installer and restart your machine to find Aero working. It may lag at times but that is what you would expect in a virtual machine with limited resources:
Enabling USB Support in Virtualbox means to be able to access USB drives plugged into your physical machine on your virtual machines. To accomplish this, you first need to download the newest version of Virtualbox (4.1.8 at the time of this writing), which is not available in the Ubuntu repositories but on the Virtualbox homepage:
Uninstall any previously installed version if present and then install the downloaded Debian package with a package installer taking care of dependencies, such as gdebi.
Next, head back to the homepage and install the Virtualbox Extension pack which supports USB 2.0.
Now you have to make yourself member of the vboxusers group. Go to the Users and Groups Settings in your Control Panel and hit Manage Groups. Scroll down to the vboxusers group and hit Properties. Check the box next to your username and click OK.
Last but not least you have to enable USB for the virtual machine. Close it if it is running and enter the Settings window. On the left panel, select USB. Check Enable USB Controller as well as Enable USB 2.0 (EHCI) Controller. Then click the button with the small green plus-symbol and add the USB device you need:
If you run the machine a USB symbol will indicate that USB is enabled and a device is running on virtual machine:
Trying to run Microsoft's Development Version of Windows 8 you might run into some problems - the two major ones being these two:
What Windows Version shall I choose in the construction of the machine?
The solution here is to choose the appropriate version of Windows 7. If you downloaded the 32 bit edition, choose Windows 7 32 bit, same for 64 bit.
When I start the machine I get some error!
Starting the machine for the first time you will most likely get the error stating:
"Windows failed to start. A recent hardware or software change might be the cause."
Info: An unexpected error has occured.
This is what you are shown:
To fix this, stop the machine and enter its settings. Go to Settings > System and check Enable IO APIC:
Exit the settings and start the machine again. You should now be able to configure the installation.